OVER FIfty years gone, Jacqueline Kennedy became the First Lady of the U.S., the spouse of the President. Two years later, following his assassination, and the sympathy it generated, she became the most potentially influential woman in the world. She might have used that heartfelt power for great human purpose; she might have marshaled the activity to locate a cure for cancer, or greatly reduce poverty. Instead, she married money (Aristotle Onassis) and became a shadow of history. She was born wealthy, she died the same way; nothing more, sad to recall. TOM TIEDE